Weeks counting question

I was always under the impression that the 40 weeks starts when you ovulated .. but I have a friend telling me that she’s technically 6 weeks pregnant when she ovulated 4 weeks ago. So I tried googling, and it does say weeks are counted based on when your last period started.

Is this right? Or is it from when you ovulated? Was I really wrong about this the whole first time ?? My cycle is longer than most, so last period started on Jan 5th, I think I ovulated around the 27th, and expected my period yesterday but got the positive instead .

Comments (3)

Most docs will go off your last menstrual period, off the assumption that most women ovulate 14 days after their period begins. That's where the assumption of 40 weeks = a term pregnancy. This is what your friend is using.

Fetal age is measured from the date of conception. Again, assuming that you ovulate 14 days from the first day of your period, you would subtract 2 weeks from your pregnancy to get fetal age.

So, technically, she is 6 weeks pregnant and her fetus is 4 weeks of age.

You are talking about two different ages.
Most docs will go off your last men...

Posted
02/14/2018

You are talking about two different ages.

Most docs will go off your last menstrual period, off the assumption that most women ovulate 14 days after their period begins. That's where the assumption of 40 weeks = a term pregnancy. This is what your friend is using.

Fetal age is measured from the date of conception. Again, assuming that you ovulate 14 days from the first day of your period, you would subtract 2 weeks from your pregnancy to get fetal age.

So, technically, she is 6 weeks pregnant and her fetus is 4 weeks of age.

So when people say I’m 13 weeks pregnant.. which are they referring to? This is my second pregnancy and I never once had a question in my mind about this. I think I’m just overthinking things now!

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